CCD diagnostics and 04/12/2003 data

1
CCD diagnostics and 04/12/2003 data

• Talk outline
• Introduction to CCD use in PETRA laserwire
• Readout and software
• Readout problems
• Analysis of images
• Results for scans of 04/12/2003
• Summary of results
• Near term future work
• Summary

2
CCD Diagnostics

• System
• 2 cameras
• Pre/post IP
• Image IP laser spot
• Basler A302f
• Camera specifications
• Monochrome
• 8bit ADC
• 780-582 resolution
• 8.3 ?m
• 30 fps
• Shutter/Gain/Brightness
• Triggered operation
• Firewire
• External line
• Small footprint

3
Readout software

• Firewire
• Digital
• No readout card required or grabber
• BCAM driver simple API
• Cable lengths (lt10m)
• Readout
• C library
• Simple to use
• Tied to Microsoft
• No problem now (Labview)
• Multiple file formats (ascii, bmp)
• MFC based windows executable
• Fast (25-30 fps)
• See images directly as DAQ runs
• Upgrade for next run
• Triggered image acquisition
• Multiple cameras
• Analysis included

4
Readout problems

• Trigger
• Laser 30 Hz CCD 30 fps
• Empty frames
• Partial images
• Recently found
• Only occurs in 1st scan
• Cause unknown
• Laser damage
• Care must be taken not to damage devices
• Filtering
• Currently use OD 2-5 ND filters
• Reflection reduction in intensity

5
CCD image analysis

• Analysis procedure
• Delete burn marks
• Projections x and y
• Fit background and subtract
• Fit Signal
• Mean/RMS calculation
• Fit signal and background
• Fit in 2D?
• Average over all images for a scan point
• Important to remember
• Area of interest (AoI)
• Fits and mean/RMS calculation
• ?70 pixels
• Errors on pixel values
• Constant?
• Dependent on signal?
• Propagation through to background subtraction

Raw projection
Background subtracted
6
CCD Background

• Problematic when
• Laser mode non-Gaussian
• Shutter
• Ambient light noise should be reduced
• Source of background
• Ambient light
• Diffuse laser reflections?
• Electronics noise
• Thermal?
• Accelerator induced electronics noise?
• Define AoI!

7
CCD analysis Low Current Scan

• Data taking
• 10-30 frames/camera/scan point before calorimeter
  measurement

8
CCD analysis High Current Scan

• Data taking
• 50 frames/camera/scan point before calorimeter
  measurement
• 30 frames too low.

9
CCD calibration summary

• Summary of CCD/scanner results
• Mean mean position / scanner voltage
• Fit-? Gaussian mean position / scanner voltage
• RMS average RMS
• Fit-? average Gaussian width
• Calibration
• Fit and simple calculation consistent
• Low and high current scans are not consistent!

Camera 1 Camera 1 Camera 2 Camera 2
Scan1 Scan 2 Scan 1 Scan 2
Mean ?m/volt 74.8?0.6 70.1?0.5 71.2?00.6 65.9?0.6
Fit-? ?m/volt 75.4?0.6 70.4?0.5 71.3?0.7 66.1?0.7
RMS ?m 163.1?0.5 164.0?0.6 141.2?0.5 143.8?0.6
Fit-? ?m 160.5?0.8 164.6?0.9 138.9?0.8 140.4?0.9
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Future work

• Analysis
• Gain/Brightness tuning loop
• Online analysis fitting etc
• Trigger
• 100 filled images
• Camera from RHUL, kitted out PC _at_ UCL
• Cooling/Radiation
• Temperature monitoring
• Investigate cooling options
• Background
• Background levels with/without
• PETRA beam
• Laser
• Area of Interest
• Calibration
• CCD to chamber centre

11
Short term developments

• Trigger
• Signal generator
• Pulse generator with delay (trigger signal)
• LED (for fake signal)
• Stephen Malton
• Software (triggered version is quite complicated)
• Testing
• Large increase in good CCD data factor 2-3
• Environment monitoring
• Damaged 2 cameras last year!
• Temperature
• Humidity
• Radiation
• Ambient light (background)
• Insert during next visit?

12
Longer term

• High speed scanning
• CMOS technology
• Basler 00
• 500 fps _at_ 1Mpixel
• 7000 fps maximum
• More radiation hard
• Even faster scanning with multiple laser pulses
  per
• Larger dynamic range
• Basler A302f
• 8 bit
• How about 12-16 bit output?
• Better signal to noise
• Basler A600
• Effective 16bit output _at_ VGA resolution

13
Summary

• First use of CCDs during scan
• Fit and simple calculation consistent
• Low and high current scans are not consistent!
• Much to be done
• Calibration
• Analysis
• Software
• Background
• Reliability